Influence of medial and lateral imaging plane inclination on assessment of trochlear depth, sulcus angle, and facet asymmetry in the setting of trochlear anatomy: a cadaveric study.

PURPOSE: (1) to assess the influence of medial or lateral imaging plane inclination on the measurement of sulcus angle, trochlear depth, and facet asymmetry on transverse cross-sectional images. (2) to assess the effect of measurement level (height) on these respective parameters. MATERIALS AND METHODS: Twenty dry femurs (9 left, 11 right) were imaged with CT. A 3D dataset was obtained from which axial images were reconstructed in the ideal plane without inclination as well as with 8° of medial and lateral inclination. Sulcus angle, trochlear depth, and facet asymmetry were measured on the 3 image sets. In addition, the measurements were performed at 5 mm and 10 mm from the superior margin of the medial trochlear facet. Statistical analysis consisted of the Wilcoxon test and calculation of measurement variation. RESULTS: There were no statistically significant differences between the indicated measurements on the reference set compared to medial or lateral inclination. All measurements were significantly different depending on measurement height. CONCLUSION: Medial or lateral inclination in the transverse imaging plane of 8° does not influence the values of typical parameters used for the assessment of trochlear dysplasia. The measurement height has a significant influence, and a consensus should be found as to which is the optimal measurement height.

Study protocol: a single-blind, multi-center, randomized controlled trial comparing dynamic intraligamentary stabilization, internal brace ligament augmentation and reconstruction in individuals with an acute anterior cruciate ligament rupture: LIBRƎ study.

BACKGROUND: The current gold standard for the treatment of an anterior cruciate ligament (ACL) rupture is reconstruction with tendon graft. Recently, two surgical ACL repair techniques have been developed for treating an acute ACL rupture: Dynamic Intraligamentary Stabilization (DIS, Ligamys®) and Internal Brace Ligament Augmentation (IBLA, InternalBrace™). We will conduct a single-blind, multi-center, randomized controlled trial which compares DIS, IBLA and reconstruction for relative clinical efficacy and economic benefit. METHODS: Subjects, aged 18-50 years, with a proximal, primary and repairable ACL rupture will be included. DIS is preferably performed within 4 weeks post-rupture, IBLA within 12 weeks and reconstruction after 4 weeks post-rupture. Patients are included in study 1 if they present within 0-4 weeks post-rupture and surgery is feasible within 4 weeks post-rupture. Patients of study 1 will be randomized to either DIS or IBLA. Patients are included in study 2 if they present after 4 weeks post-rupture and surgery is feasible between 5 and 12 weeks post-rupture. Patients of study 2 will be randomized to either IBLA or reconstruction. A total of 96 patients will be included, with 48 patients per study and 24 patients per study arm. Patients will be followed-up for 2 years. The primary outcome is change from baseline (pre-rupture) in International Knee Documentation Committee score to 6 months post-operatively. The main secondary outcomes are the EQ-5D-5 L, Tegner score, Lysholm score, Lachman test, isokinetic and proprioceptive measurements, magnetic resonance imaging outcome, return to work and sports, and re-rupture/failure rates. The statistical analysis will be based on the intention-to-treat principle. The economic impact of the surgery techniques will be evaluated by the cost-utility analysis. The LIBRƎ study is to be conducted between 2018 and 2022. DISCUSSION: This LIBRƎ study protocol is the first study to compare DIS, IBLA and ACL reconstruction for relative clinical efficacy and economic benefit. The outcomes of this study will provide data which could aid orthopaedic surgeons to choose between the different treatment options for the surgical treatment of an acute ACL rupture. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov; NCT03441295. Date registered 13.02.2018.

The TRAC-PS dual radius total knee arthroplasty : Disappointing medium and long terms results.

The TRAC prosthesis is a dual radius, mobile bearing, posterior stabilized prosthesis, to increase stability by optimizing contact area and control wear using a mobile polyethylene. Between February 1995 and January 2000, a single surgeon performed a continuous series of 85 TRAC-PS TKAs in 85 patients at the University Hospital Brussels. A retrospective review on patient charts was performed. Patients available were scored clinically using the Knee Society Score, WOMAC osteoarthritis index, SF 36 and a Visual Analogue Scale for pain. 43 patients had died at time of evaluation, three were unavailable for examination due to bad general health and five were lost to follow up. The remaining 35 patients were examined with a mean follow-up of 13 years. The mean age of the patients at follow up was 83 years. The mean WOMAC score was 78,4(SD 17,9). The mean Knee Society Score was 86.8(SD 8,4) clinical and 42,6(SD 28) functional. The mean range of flexion was 105°. The mean SF-36 score was 59,8(SD 15,4). The VAS for pain was 6(SD 9). With revision (8 cases) as endpoint, survival rate of the prosthesis was estimated to be 92% at 13 years. Twenty-three Serious Adverse Events (28%) in 17 patients, related to the prosthesis were registered in this patient group. Long term results of this prosthesis were satisfying but a large number of serious adverse events led to abandonment of the TRAC-prosthesis.

The influence of freezing on the tensile strength of tendon grafts : a biomechanical study.

We investigated the influence of freezing on the tensile strength of fresh frozen tendon grafts. The biomechanical characteristics of tendons that are less commonly used in knee surgery (tibialis anterior, tibialis posterior, peroneus longus and medial and lateral half of Achilles tendons) were compared to those of a semitendinosus and gracilis graft harvested from the same 10 multi-organ donors. All right side tendons constituted the study group and were frozen at -80 degrees C and thawed at room temperature 5 times. All left side tendons were frozen at -80 degrees C and thawed at room temperature once. There were 59 tendons in the control group and 56 in the study group. The looped grafts were clamped at one side using a custom-made freeze clamp and loaded until failure on an Instron 4505 testing machine. The average ultimate failure load was not significantly different between the control and the study group (p > 0.05). The failure load of the medial tendon Achilles was the lowest in both study and control group (p < 0.001). There was no significant difference in maximum stress, maximum displacement, maximum strain and stiffness between the control and study group (p > 0.05). From our study, we conclude that freezing tendons at -80 degrees C and thawing several times does not influence the maximum load, maximum stress, maximum displacement, maximum strain and stiffness. The medial half of the Achilles tendon is clearly the weakest tendon (p < 0.001). These findings show that tendon grafts can be frozen at -80 degrees C and thawed at room temperature several times without altering their biomechanical properties.

The Pentaconcept in skeletal tissue engineering. A combined approach for the repair of bone defects.

Tissue engineering has become a hot topic in modern medicine. Its application in a surgical setting, such as for the treatment of skeletal defects, still has to tackle some problems that might look simple at first sight, but need a well-structured handling combining surgery and science, with in a central position the patient, who is both cell donor and receptor of the tissue engineered end product. To achieve this goal in a clinical setting, a five steps pathway is described and designated as the Pentaconcept, integrating all ingredients for successful reconstructive procedures.

Reduction of treatment time in external ring fixation using the monofix device.

One of the disadvantages of the Ilizarov method is the long treatment time needed for extensive lengthening or complex deformity correction. To minimize the discomfort of the circular frame the authors have introduced a 'frame reduction' technique in which the ring frame is converted towards a unilateral fixator, the 'Monofix'. Both its efficacy and patient satisfaction encouraged the authors to apply this method on a routine basis since 1998 for lower and upper limb corrections. The technique is demonstrated, its indications and potential problems are discussed.

Ultrasound of Lipomatosis of Nerve Associated with Macrodactyly: 'Spaghetti and Chocolate Cookie' Appearance.

We studied the US imaging findings of lipomatosis of nerve and macrodystrophia lipoma in three patients. Three patients were seen at three affiliated institutions with an enlarged digit. They all underwent US, subsequently followed by an MRI study. The nerves showed marked enlargement and extension over a length of 9-16 cm. Digital branches were always involved. The appearance on cross section was an enlarged hyperechoic endoneurium with inlying thickened and hypoechoic fascicles. On transverse images this resulted in a 'chocolate cookie' aspect and in the long axis a 'spaghetti-like' image. The US appearance of lipomatosis of nerve, not unlike MRI, is rather typical. With US, care should be taken in areas that are more difficult to assess as the sole of the foot, or where the 'chocolate cookie' appearance is not so obvious, such as the digits.

Outpatient parenteral antibiotic therapy for the treatment of prosthetic knee and hip infections in Belgium, a cost minimization analysis.

OBJECTIVES: Prosthetic joint infections (PJI) are treated with prolonged periods of intravenous (IV) antibiotics combined with one or more appropriate surgical procedures. In Belgium, patients receive their IV treatments as inpatients, whereas in other parts of the world similar IV antibiotics can be given as outpatient parenteral antibiotic therapy (OPAT), without jeopardising patient outcomes. The purpose of this paper was to analyse the financial feasibility of OPAT for PJI in Belgium. METHODS: Patients with PJI treated with a two-stage revision between January 2013 and June 2016 were selected for analysis of in-hospital costs. An OPAT cost simulation was made for comparable lengths of stay, for the different antimicrobial regimens used. A cost minimization analysis comparing the non-OPAT costs and the OPAT cost simulation was performed, with a sensitivity analysis accounting for cost uncertainties. RESULTS: Based on the financial data of 12 two-stage revisions and 4 different antibiotic regimens, the average simulated cost difference for OPAT was €2.402 surplus for the patient, €-25.950 for health care and €-23.548 in total. CONCLUSION: Projected cost savings for OPAT-treatment of PJI are substantial. However, OPAT within the current Belgian system was significantly more expensive for the patients. This can be attributed to the Belgian health insurance system; its current reimbursement regulations prevent OPAT from truly making a breakthrough in Belgium.

Evaluating lower limb kinematics and pathology with dynamic CT.

Evaluating musculoskeletal conditions of the lower limb and understanding the pathophysiology of complex bone kinematics is challenging. Static images do not take into account the dynamic component of relative bone motion and muscle activation. Fluoroscopy and dynamic MRI have important limitations. Dynamic CT (4D-CT) is an emerging alternative that combines high spatial and temporal resolution, with an increased availability in clinical practice. 4D-CT allows simultaneous visualization of bone morphology and joint kinematics. This unique combination makes it an ideal tool to evaluate functional disorders of the musculoskeletal system. In the lower limb, 4D-CT has been used to diagnose femoroacetabular impingement, patellofemoral, ankle and subtalar joint instability, or reduced range of motion. 4D-CT has also been used to demonstrate the effect of surgery, mainly on patellar instability. 4D-CT will need further research and validation before it can be widely used in clinical practice. We believe, however, it is here to stay, and will become a reference in the diagnosis of lower limb conditions and the evaluation of treatment options. Cite this article: Bone Joint J 2021;103-B(5):822-827.

The John Insall Award: Both morphotype and gender influence the shape of the knee in patients undergoing TKA.

UNLABELLED: There is an ongoing debate whether gender differences in the dimensions of the knee should influence the design of TKA components. We hypothesized that not only gender but also the patient's morphotype determined the shape of the distal femur and proximal tibia and that this factor should be taken into account when designing gender-specific TKA implants. We reviewed all 1000 European white patients undergoing TKA between April 2003 and June 2007 and stratified each into one of three groups based on their anatomic constitution: endomorph, ectomorph, or mesomorph. Of the 250 smallest knees, 98% were female, whereas 81% of the 250 largest knees were male. In the group with intermediate-sized knees, female knees were narrower than male knees. Patients with smaller knees (predominantly female) demonstrated large variability between narrow and wide mediolateral dimensions irrespective of gender. The same was true for larger knees (predominantly male). This variability within gender could partially be explained by morphotypic variation. Patients with short and wide morphotype (endomorph) had, irrespective of gender, wider knees, whereas patients with long and narrow morphotype (ectomorph) had narrower knees. The shape of the knee is therefore not only dependent on gender, but also on the morphotype of the patient. LEVEL OF EVIDENCE: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Autologous chondrocyte implantation versus microfracture for knee cartilage injury: a prospective randomized trial, with 2-year follow-up.

The objective was to evaluate the functional performance over a 2-year period following autologous chondrocyte implantation (ACI) in an open knee procedure compared to microfracture. Objective functional outcome was studied as secondary analysis in a subgroup of patients, in a randomized clinical trial, with concealed allocation and independent evaluators. Sixty-seven patients with local cartilage defect, with a mean size of 2.4 cm(2) (SD 1.5) of the femoral condyle of the knee were included. Thirty-three patients underwent the microfracture and 34 the ACI procedure. An identical rehabilitation protocol was implemented for both groups. Active knee flexion and extension range, anterior laxity, knee extension strength (concentric at 60 degrees/s) and single leg hop performance (single hop, crossover triple hop and 6 m timed hop test) were evaluated pre-surgery and at 6, 9,12 and 24 months post-surgery. We calculated the symmetry index for individual and four performance tests pooled. Mixed linear model analyses were used with confidence interval set at 95%. The change over 2 years for the pooled performance-based tests was comparable between the two treatment arms. At 2 years, 70% (38/54) of all patients returned to >85% symmetry in overall functional performance. A decrease in functional performance at 6 months following ACI resulted in slower recovery at 9 and 12 months compared to microfracture. Rehabilitation following both cartilage repair procedures is a lengthy process. At 2 years after surgery, ACI patients have similar overall functional outcome compared to microfracture patients.

Ilizarov treatment for aseptic delayed union or non-union after reamed intramedullary nailing of the femur.

The authors reviewed eight patients treated with an Ilizarov frame for a non-infected delayed union or non-union after reamed intramedullary nailing of the femoral diaphysis. The hardware was completely removed in all cases but two, in which the distal fragment of a broken nail was left in situ. In five cases without shortening, progressive compression was applied. In the other three patients a simultaneous lengthening was performed using an additional percutaneous osteotomy. All patients achieved a good consolidation, with an average time to healing of 32 weeks and restoration of length and alignment if necessary. Bone grafting was never required, illustrating the sufficient biological potential for repair in non-infected femoral non-union.

Arthroscopy of the knee in elderly patients: cartilage lesions and their influence on short term outcome. A retrospective follow-up of 183 patients.

We reviewed all patients of 65 years and older (n=183), who underwent a knee arthroscopy between 2004 and 2005. The purpose of our study was to determine the frequency and severity of cartilage lesions and their influence on short-term clinical outcome. Signs of osteoarthritis (OA) were absent or minor on pre operative plain radiographs in 30.5% of patients, but only 5.3% of patients were found during arthroscopy to have no obvious cartilage lesions. WOMAC and KOOS scores did not clearly correlate with severity of cartilage damage, but some WOMAC and KOOS subscales scored significantly lower when cartilage lesions were located on the lateral side. Forty-one patients eventually underwent TKA after a mean period of 14 months. In conclusion, cartilage lesions were visualized in almost every case even when pre-operative radiographs suggested differently. The higher the Kellgren-Lawrence grade of cartilage lesions on preoperative radiographs, the higher the risk for a TKA in the short term. Forty-seven percent of patients with Kellgren-Lawrence grade 4 lesions needed a TKA during the time period of the study.

Clinical and Radiographic Outcome of Gap Balancing Versus Measured Resection Techniques in Total Knee Arthroplasty.

BACKGROUND: There is no consensus regarding superiority between gap balancing (GB) and measured resection (MR) techniques to implant total knee arthroplasties. In a multicenter setup, we compared both techniques using the same prosthesis. METHODS: We included 262 balanSys posterior-stabilized total knee arthroplasties from 4 centers: 3 using the MR (n = 162) and one using the GB technique (n = 100), without navigation. RESULTS: There was no significant difference in the Knee Society Score or visual analog scale pain at 2- and 7-year follow-up. The visual analog scale for satisfaction was significantly better in the MR group at 2 but not at 7 years. We found a significantly higher average valgus in the GB group, but the overall alignment was within 2° of neutral on the full-leg radiographs. There were no significant differences concerning radiolucency and survival. CONCLUSIONS: We found no significant differences in the functional outcome, pain, alignment, or survival, but a tendency toward better function using MR and better survival with GB.

Treatment of central sensitization in patients with chronic pain: time for change?

Introduction: Given our improved understanding of the role of central sensitization (CS) in many patients with chronic pain, it seems rational to account for CS during treatment. Areas covered: First, the treatment rationale based on the complex mechanisms underlying CS in patients having chronic pain is presented. Second, emphasis is given to explaining the concept of CS when providing treatment, as well as why patients and clinicians should focus on long-term rather than short-term treatment effects. Third, possible pharmacological and non-pharmacological treatment options are discussed. Expert opinion: Centrally acting drugs such as tricyclic compounds, serotonin-norepinephrine reuptake inhibitors, and α2δ ligands each target mechanisms that are often dysfunctional in patients having chronic pain and CS, but decades of clinical practice and clinical trials have not resulted in satisfactory outcomes. This comes as no surprise; CS comprises complex psycho-neuro-immunological interactions, while each of the tested drugs targets one or two of those mechanisms from a purely biomedical viewpoint. Clinicians willing to take CS into account should design an individually tailored multimodal treatment plan comprising pain neuroscience education, cognition-targeted exercise therapy, sleep management, stress management, and/or dietary intervention.

Repair of symptomatic cartilage lesions of the knee: the place of autologous chondrocyte implantation.

An increasing number of patients with cartilage defects of the knee are being treated with autologous chondrocyte implantation (ACI). To date, no clear guidelines exist for the use and indications of this technique. The BVOT and SOBCOT have established a working group to review the clinical results and the cost-effectiveness of the various treatment modalities and particularly of ACI. This group has formulated recommendations and presents a treatment algorithm based on an in-depth review of recent European and American literature, on peer-reviewed opinions of leading investigators in the field and on a comparative analysis of the clinical results and health-economic aspects of current cartilage repair techniques.

Expanded phenotypically stable chondrocytes persist in the repair tissue and contribute to cartilage matrix formation and structural integration in a goat model of autologous chondrocyte implantation.

Autologous chondrocyte implantation (ACI) is an established technique to repair joint surface defects. Although there is some indirect evidence that the expanded chondrocytes are required to achieve proper healing, the role they play in the repair process is not clear yet. To monitor the persistence and the phenotype of the injected chondrocytes in the repair tissue (RT) we have optimized a fluorescent labeling protocol for articular chondrocytes, which allows cell tracking in vivo for up to 14 weeks, using the fluorescent dye PKH26. We have combined in vivo cell tracking, with the immune-detection of collagen type II protein in a goat model of ACI. Our data indicate that the implanted cells can persist for at least 14 weeks in the defects, can participate in the integration with the surrounding tissues, and become structural part of the RT, rich in collagen type II and sulfated proteoglycans. Albeit with a small number of samples, our data provide proof of principal that the implanted chondrocytes can contribute to structural cartilage repair in a goat model of ACI.

Long-term Subjective, Clinical, and Radiographic Outcome Evaluation of Meniscal Allograft Transplantation in the Knee.

BACKGROUND: Although meniscal allograft transplantation (MAT) has been performed for nearly 30 years, there are few long-term published studies of the technique. HYPOTHESIS/PURPOSE: The goal of this study was to report the long-term results of a patient cohort whose medium-term results have been reported and to evaluate whether the results are maintained in the long term or deteriorate after a certain period. The hypothesis was that the subjective, clinical, and radiographic results are consistent in the long term without significant deterioration. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty patients from the original cohort of 49 patients (50 MATs) who underwent MAT at least 9 years before this study were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS); Lysholm, Tegner, and Short Form-36 scores; and a visual analog score for pain. A standardized clinical examination was performed to objectively evaluate knee-related symptoms. Standard weightbearing radiographs, including a full-leg standing radiograph, were performed to evaluate joint space narrowing and any progression of osteoarthritis and malalignment. These results, at a mean follow-up time of 12 years and 8 months (152 months; range, 112-216 months), were compared with the preoperative data and the outcome results at medium-term follow-up (mean, 8 years and 9 months). RESULTS: Of the original 49 patients, 6 (12.2%) required conversion to a total knee arthroplasty during the study period and were considered failures, and 17 (34.7%) required a second surgical procedure during the study period. Excluding the 6 total knee arthroplasty cases, 90% of patients reported being very satisfied or satisfied and would undergo the procedure again. Only 1 patient reported not wanting to undergo the procedure again. Results of the visual analog score, KOOS and all KOOS subscales, Lysholm, and Short Form-36 all showed a statistically significant improvement at estimated follow-up periods of 7.5 and 12.5 years compared with preoperative scores. There was no statistically significant difference for these scores between 7.5 and 12.5 years postoperatively. Despite the improvement in outcome scores, the Tegner activity level score remained unchanged during the entire follow-up period. Regarding radiographic outcomes, there was a progressive increase in the Kellgren-Lawrence rating over the study period. There was a statistically significant (P = .0208) progressive joint space narrowing between estimates at the 7.5-year (5.45 mm) and 12.5-year (4.95 mm) follow-up. However, there was no statistically significant (P = .6724) difference in absolute value of alignment deviation from the 0° mechanical axis between 7.5 years (2.32°) and 12.5 years (2.51°) postoperatively. There was no difference between medial and lateral transplants. CONCLUSION: Despite an increase in joint space narrowing, MAT resulted in significant improvements in pain and functional outcomes over the study period. There was no change in these improvements between the medium- and long-term follow-up period. This study confirms the good and consistent results found in the literature concerning satisfaction, pain resolution, and functional scores at long-term follow-up.

Validation of a finite element model of a unilateral external fixator in a rabbit tibia defect model.

In case of large segmental defects in load-bearing bones, an external fixator is used to provide mechanical stability to the defect site. The overall stiffness of the bone-fixator system is determined not only by the fixator design but also by the way the fixator is mounted to the bone. This stiffness is an important factor as it will influence the biomechanical environment to which tissue engineering scaffolds and regenerating tissues are exposed. A finite element (FE) model can be used to predict the system stiffness. The goal of this study is to develop and validate a 3D anatomical FE model of a bone-fixator system which includes a previously developed unilateral external fixator for a large segmental defect model in the rabbit tibia. It was hypothesized that the contact interfaces between bone and fixator screws play a major role for the prediction of the stiffness. In vitro mechanical testing was performed in order to measure the axial stiffness of cortical bone from mid-shaft rabbit tibiae and of the tibia-fixator system, as well as the bending stiffness of individual fixator screws, inserted in bone. µCT-based case-specific FE models of cortical bone and SCREW-BONE specimens were created to simulate the corresponding mechanical test set-ups. The Young's modulus of rabbit cortical bone as well as appropriate screw-bone contact settings were derived from those FE models. We then used the derived settings in an FE model of the tibia-fixator system. The difference between the FE predicted and measured axial stiffness of the tibia-fixator system was reduced from 117.93% to 7.85% by applying appropriate screw-bone contact settings. In conclusion, this study shows the importance of screw-bone contact settings for an accurate fixator stiffness prediction. The validated FE model can further be used as a tool for virtual mechanical testing in the design phase of new tissue engineering scaffolds and/or novel patient-specific external fixation devices.

Tissue engineering approaches for osteoarthritis.

With the ageing of the population and the major advances in targeted drug treatments, there is in medicine a shift in attention from survival towards quality of life. Therefore new challenges are emerging in modern health care. Preventive and personalized medicine have been identified as key steps in this context. New targeted biologicals for musculoskeletal diseases such as chronic arthritis have entered daily clinical practice, thereby not only controlling symptoms and signs, inflammation and destruction, but also maintaining function of the joints. The last aspect is essential for the independence of the individual and critical for the quality of life. Since the lifespan of prosthetic devices will always remain limited, new treatment approaches to repair skeletal structures need to be devised for the young and middle aged individuals with skeletal and joint damage caused by either congenital, traumatic, or inflammatory conditions. It is believed that regenerative medicine and more specifically tissue engineering may fill this void to some extent. Indeed, recent cellular therapeutics and combination products, now resorting under a new regulatory class of Advanced Medicinal Therapeutic Products, provide indications that progress is being made with clinically relevant outcomes in well-defined patient populations. For osteoarthritis, a joint disease leading to joint decompensation, novel tissue engineering therapies are being explored and, although most of the developments are still in early phase clinical studies, there are sufficient positive signals to pursue these novel therapeutic approaches in clinics. This article is part of a Special Issue entitled "Osteoarthritis".